WO2017078062A1

WO2017078062A1 - Base station, wlan termination node, and wireless terminal

Info

Publication number: WO2017078062A1
Application number: PCT/JP2016/082580
Authority: WO
Inventors: 勝裕三井; 優志長坂; 空悟守田
Original assignee: 京セラ株式会社
Priority date: 2015-11-06
Filing date: 2016-11-02
Publication date: 2017-05-11
Also published as: JPWO2017078062A1; US20180255601A1; EP3373693A1

Abstract

A wireless terminal according to an embodiment is connected to a base station of a WLAN. The wireless terminal receives, from the base station, a setting message for instructing a connection process between the wireless terminal and the WLAN, receives timer information, which is included in the setting message, for setting a timer for determining a failure of the connection process between the wireless terminal and the WLAN, starts the timer based on the timer information, determines that the connection process has failed when the timer expires, and transmits a failure message indicating the failure of the connection process to the base station.

Description

Base station, WLAN terminal node, and wireless terminal

The present invention relates to a base station, a WLAN termination node, and a wireless terminal in a system that links a WLAN with a WWAN.

In recent years, wireless terminals compatible with both WWAN (Wireless Wide Area Network) communication and WLAN (Wireless Local Area Network) communication have been widely used.

In order to provide high-speed and large-capacity communication services for such wireless terminals, 3GPP (Third Generation Partnership Project) is studying a technique for strengthening the cooperation between WWAN and WLAN.

As one such technique, a method in which a WWAN base station transmits a setting message for instructing connection processing with a WLAN to a wireless terminal connected to the WWAN base station has been studied. The connection process between the wireless terminal and the WLAN may be referred to as “association”.

The wireless terminal according to the first aspect is connected to a WWAN base station. The wireless terminal receives a setting message for instructing a connection process between the wireless terminal and the WLAN from the base station, and is included in the setting message between the wireless terminal and the WLAN. A process for receiving timer information for setting a timer for determining a failure in connection processing, a process for starting a timer based on the timer information, and a determination that the connection process has failed when the timer expires And a controller that performs a process of transmitting a failure message indicating failure of the connection process to the base station.

The base station according to the second aspect is a WWAN base station. The base station transmits, to a WLAN terminal node having an interface with the base station, a request message for requesting resource allocation to a wireless terminal connected to the base station, and an acknowledgment for the request message. A control unit is provided for performing a process of receiving a response message from the WLAN terminal node and a process of transmitting a setting message for instructing a connection process between the wireless terminal and the WLAN to the wireless terminal. The control unit includes timer information for setting a timer for determining failure of connection processing between the wireless terminal and the WLAN in the setting message.

The base station according to the third aspect is a WWAN base station. The base station transmits, to a WLAN terminal node having an interface with the base station, a request message for requesting resource allocation to a wireless terminal connected to the base station, and an acknowledgment for the request message. A process of receiving a response message from the WLAN terminal node, a process of transmitting a setting message for instructing a connection process between the wireless terminal and the WLAN, and a setting completion message for the setting message. A process for receiving from the wireless terminal, and a process for starting a timer for determining a failure in the connection process between the wireless terminal and the WLAN in response to the reception of the acknowledgment message or the setting completion message. The control part which performs these is provided.

The WLAN termination node according to the fourth aspect has an interface with a WWAN base station. The WLAN termination node receives from the base station a request message for requesting resource allocation to a radio terminal connected to the base station, and transmits an acknowledgment message to the request message to the base station. And a control unit that performs a process of starting a timer for determining a failure of a connection process between the wireless terminal and the WLAN in response to the transmission of the acknowledgment message.

The base station according to the fifth aspect is a WWAN base station. The base station transmits, to a WLAN terminal node having an interface with the base station, a request message for requesting resource allocation to a wireless terminal connected to the base station, and an acknowledgment for the request message. A process of receiving a response message from the WLAN termination node, a process of transmitting a setting message for instructing a connection process between the wireless terminal and the WLAN, and a failure message indicating failure of the connection process A controller that performs a process of determining that the connection process has failed in response to receiving a failure notification indicating that the connection process has failed from the wireless terminal. Prepare.

It is a figure which shows the whole system configuration | structure which concerns on embodiment. It is a figure which shows the network interface which concerns on embodiment. It is a protocol stack figure of a radio | wireless interface. It is a block diagram of UE (radio terminal). It is a block diagram of eNB (base station). It is a block diagram of WT (WLAN termination node). It is a figure which shows the radio | wireless protocol structure of LWA. It is a figure which shows a WT addition procedure (WT Addition procedure). It is a flowchart which shows the operation pattern 1 of eNB which concerns on 1st Embodiment. It is a flowchart which shows the operation pattern 2 of eNB which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of UE which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of eNB which concerns on 2nd Embodiment. It is a flowchart which shows operation | movement of WT which concerns on 3rd Embodiment. It is a flowchart which shows operation | movement of UE which concerns on 4th Embodiment.

[Outline of Embodiment]
The wireless terminal according to the embodiment is connected to a WWAN base station. The wireless terminal receives a setting message for instructing a connection process between the wireless terminal and the WLAN from the base station, and is included in the setting message between the wireless terminal and the WLAN. A process for receiving timer information for setting a timer for determining a failure in connection processing, a process for starting a timer based on the timer information, and a determination that the connection process has failed when the timer expires And a controller that performs a process of transmitting a failure message indicating failure of the connection process to the base station.

In the embodiment, the control unit stops the timer when the connection process is successful during the operation of the timer.

In the embodiment, when the connection process is successful during the operation of the timer, the control unit transmits a success notification indicating the success of the connection process to the base station.

The base station according to the embodiment is a WWAN base station. The base station transmits, to a WLAN terminal node having an interface with the base station, a request message for requesting resource allocation to a wireless terminal connected to the base station, and an acknowledgment for the request message. A control unit is provided for performing a process of receiving a response message from the WLAN terminal node and a process of transmitting a setting message for instructing a connection process between the wireless terminal and the WLAN to the wireless terminal. The control unit includes timer information for setting a timer for determining failure of connection processing between the wireless terminal and the WLAN in the setting message.

The base station according to the embodiment is a WWAN base station. The base station transmits, to a WLAN terminal node having an interface with the base station, a request message for requesting resource allocation to a wireless terminal connected to the base station, and an acknowledgment for the request message. A process of receiving a response message from the WLAN terminal node, a process of transmitting a setting message for instructing a connection process between the wireless terminal and the WLAN, and a setting completion message for the setting message. A process for receiving from the wireless terminal, and a process for starting a timer for determining a failure in the connection process between the wireless terminal and the WLAN in response to the reception of the acknowledgment message or the setting completion message. The control part which performs these is provided.

In the embodiment, when the base station receives a confirmation message indicating that the connection process is successful during the operation of the timer from the WLAN termination node, the control unit stops the timer. When the timer expires without the base station receiving the confirmation message from the WLAN termination node during the operation of the timer, the control unit determines that the connection process has failed.

In the embodiment, when the base station receives a success notification indicating that the connection process is successful during the operation of the timer from the wireless terminal, the control unit stops the timer. When the timer expires without the base station receiving the success notification from the wireless terminal during the operation of the timer, the control unit determines that the connection process has failed.

In the embodiment, when the timer expires, the control unit performs any one of the first to third processes. The first process is a process of requesting the WLAN end node to release resources for the wireless terminal. The second process is a process of requesting resource allocation for the wireless terminal to a WLAN terminal node different from the WLAN terminal node and requesting the WLAN terminal node to release resources for the wireless terminal. is there. The third process is a process of changing a WLAN mobility set to be set in the wireless terminal and requesting the WLAN end node to change the mobility set.

In the embodiment, the control unit performs a process of receiving a WLAN measurement report from the wireless terminal, and determines one of the first to third processes based on information included in the WLAN measurement report. To do.

The WLAN terminal node according to the embodiment has an interface with a WWAN base station. The WLAN termination node receives from the base station a request message for requesting resource allocation to a radio terminal connected to the base station, and transmits an acknowledgment message to the request message to the base station. And a control unit that performs a process of starting a timer for determining a failure of a connection process between the wireless terminal and the WLAN in response to the transmission of the acknowledgment message.

In the embodiment, when the connection process is successful during the operation of the timer, the control unit stops the timer. When the connection process does not succeed during the operation of the timer and the timer expires, the control unit determines that the connection process has failed.

In the embodiment, when the timer expires, the control unit performs a process of transmitting a failure message indicating a failure of the connection process to the base station.

In the embodiment, the control unit includes information indicating the cause of the failure of the connection process in the failure message.

The base station according to the embodiment is a WWAN base station. The base station transmits, to a WLAN terminal node having an interface with the base station, a request message for requesting resource allocation to a wireless terminal connected to the base station, and an acknowledgment for the request message. A process of receiving a response message from the WLAN termination node, a process of transmitting a setting message for instructing a connection process between the wireless terminal and the WLAN, and a failure message indicating failure of the connection process A controller that performs a process of determining that the connection process has failed in response to receiving a failure notification indicating that the connection process has failed from the wireless terminal. Prepare.

In the embodiment, the control unit that determines that the connection process has failed performs any one of the first to third processes. The first process is a process of requesting the WLAN end node to release resources for the wireless terminal. The second process is a process of requesting resource allocation for the wireless terminal to a WLAN terminal node different from the WLAN terminal node and requesting the WLAN terminal node to release resources for the wireless terminal. is there. The third process is a process of changing a WLAN mobility set to be set in the wireless terminal and requesting the WLAN end node to change the mobility set.

[System Configuration According to Embodiment]
Hereinafter, a system configuration according to the embodiment will be described. In the embodiment, an example will be described in which the WWAN system is an LTE (Long Term Evolution) system whose specifications are defined in 3GPP.

(1) Overall System Configuration FIG. 1 is a diagram showing an overall system configuration according to the embodiment. FIG. 2 is a diagram illustrating a network interface according to the embodiment.

As shown in FIG. 1, the system according to the embodiment includes a UE (User Equipment) 100, an eNB (E-UTRAN NodeB) 200, a WLAN AP (WLAN Access Point) 300, a WT (WLAN Termination) 400, and an EPC (Evolved). (Packet Core) 500. The UE 100 corresponds to a wireless terminal. The eNB 200 corresponds to a WWAN base station. The WT 400 corresponds to a WLAN terminal node. The eNB 200 and the EPC 500 constitute a WWAN (LTE network) 10. The WLAN AP 300 and the WT 400 constitute the WLAN 20.

UE 100 supports both communication methods of LTE communication and WLAN communication. The UE 100 is a mobile device. The UE 100 supports LTE / WLAN aggregation (LWA). The configuration and LWA of the UE 100 will be described later.

ENB 200 manages one or a plurality of cells. The eNB 200 is a device that performs LTE communication with the UE 100 connected to the own cell.

The eNB 200 constitutes E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network). The eNB 200 is connected to an adjacent eNB via the X2 interface. The eNB 200 has a radio resource management (RRM) function, a routing function of user data (hereinafter simply referred to as “data”), a measurement control function for mobility control / scheduling, and the like. The configuration of the eNB 200 will be described later. “Cell” is used as a term indicating a minimum unit of a radio communication area (coverage). “Cell” is also used as a term indicating a function of performing wireless communication with the UE 100.

WLAN AP 300 is a device that performs WLAN communication with UE 100 connected to its own AP. FIG. 1 shows an example in which four WLAN APs 300-1 to 300-4 are provided in the cell coverage of the eNB 200. The eNB 200 may have a WLAN AP function. Such a scenario is referred to as a Collated scenario.

The WT 400 is a device that terminates the Xw interface that is an interface with the eNB 200. As illustrated in FIG. 2, the eNB 200 is connected to the WT 400 via the Xw interface. In the LWA, only the S1 interface is required as an interface with the EPC 500 (core network). That is, an interface between the WLAN 20 and the EPC 500 (core network) is not required. The WT 400 accommodates one or more WLAN APs 300. FIG. 1 shows an example in which the WT 400-1 accommodates two WLAN APs 300-1 and 300-2, and the WT 400-2 accommodates two WLAN APs 300-3 and 300-4.

WLAN APs 300-1 and 300-2 constitute WLAN mobility set A. The WLAN APs 300-3 and 300-4 constitute a WLAN mobility set B. The WLAN mobility set is a WLAN AP group in which the UE 100 to which LWA is applied can perform switching control between the WLAN AP 300 without depending on the control of the eNB 200. The UE 100 can switch the WLAN communication from one WLAN AP to another WLAN AP in the same WLAN mobility set transparently to the eNB 200 by using the WLAN mobility control function.

The eNB 200 notifies the UE 100 of the WLAN mobility set. The UE 100 can connect to only one WLAN mobility set at a certain time. Mobility to the WLAN AP 300 that does not belong to the current WLAN mobility set of the UE 100 is controlled by the eNB 200 based on a measurement report (WLAN measurement report) provided by the UE 100, for example. All WLAN APs 300 belonging to one WLAN mobility set share the same WT 400. All WLAN identifiers belonging to one WLAN mobility set may be part of all WLAN identifiers corresponding to one WT 400. The WLAN identifier is, for example, a BSSID (Basic Service Set Identifier), a HESSID (Homogeneous Extended Service Set Identifier), or an SSID (Service Set Identifier).

The EPC 500 is connected to the eNB 200 via the S1 interface. The EPC 500 corresponds to a core network. As shown in FIG. 2, the EPC 500 includes an MME (Mobility Management Entity) 500C and an S-GW (Serving-Gateway) 500U. MME500C performs various mobility control etc. with respect to UE100. The S-GW 500U performs data transfer control.

(2) Radio Interface FIG. 3 is a protocol stack diagram of the radio interface. As shown in FIG. 3, the radio interface protocol is divided into the first to third layers of the OSI reference model. The first layer is a physical (PHY) layer. The second layer includes a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, and a PDCP (Packet Data Convergence Protocol) layer. The third layer includes an RRC (Radio Resource Control) layer.

The physical layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control signals are transmitted between the physical layer of the UE 100 and the physical layer of the eNB 200 via a physical channel.

The MAC layer performs data priority control, retransmission processing by hybrid ARQ (HARQ), random access procedure, and the like. Data and control signals are transmitted between the MAC layer of the UE 100 and the MAC layer of the eNB 200 via a transport channel. The MAC layer of the eNB 200 includes a scheduler. The scheduler determines the uplink / downlink transport format (transport block size, modulation / coding scheme (MCS)) and the resource blocks allocated to the UE 100.

The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and the physical layer. Data and control signals are transmitted between the RLC layer of the UE 100 and the RLC layer of the eNB 200 via a logical channel.

The PDCP layer performs header compression / decompression and encryption / decryption.

The RRC layer is defined only in the control plane that handles control signals. Messages for various settings (RRC messages) are transmitted between the RRC layer of the UE 100 and the RRC layer of the eNB 200. The RRC layer controls the logical channel, the transport channel, and the physical channel according to establishment, re-establishment, and release of the radio bearer. When there is a connection (RRC connection) between the RRC of the UE 100 and the RRC of the eNB 200, the UE 100 is in the RRC connected mode (connected mode). When there is no connection between the RRC of the UE 100 and the RRC of the eNB 200, the UE 100 is in the RRC idle mode (idle mode).

The NAS (Non-Access Stratum) layer located above the RRC layer performs session management and mobility management.

(3) Configuration of Radio Terminal FIG. 4 is a block diagram of the UE 100 (radio terminal). As illustrated in FIG. 4, the UE 100 includes an LTE communication unit 110, a WLAN communication unit 120, and a control unit 130.

The LTE communication unit 110 performs LTE communication under the control of the control unit 130. The LTE communication unit 110 may execute part of the LTE protocol. The LTE communication unit 110 includes an antenna, a transmitter, and a receiver. The transmitter converts a baseband signal (transmission signal) output from the control unit 130 into an LTE radio signal. The transmitter transmits an LTE radio signal from the antenna. The receiver converts the LTE radio signal received by the antenna into a baseband signal (received signal). The receiver outputs a baseband signal to the control unit 130. LTE communication is generally performed in a license band.

The WLAN communication unit 120 performs WLAN communication under the control of the control unit 130. The WLAN communication unit 120 may execute part of the WLAN protocol. The WLAN communication unit 120 includes an antenna, a transmitter, and a receiver. The transmitter converts a baseband signal (transmission signal) output from the control unit 130 into a WLAN radio signal. The transmitter transmits a WLAN radio signal from the antenna. The receiver converts the WLAN radio signal received by the antenna into a baseband signal (received signal). The receiver outputs a baseband signal to control unit 130. In general, WLAN communication is performed in an unlicensed band.

The control unit 130 performs various controls in the UE 100. The control unit 130 may execute part of the LTE protocol or may execute part of the WLAN protocol. The control unit 130 includes a processor and a memory. The memory stores a program executed by the processor and information used for processing by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of the baseband signal. The CPU performs various processes by executing programs stored in the memory. The processor executes various processes described later.

(4) Configuration of Base Station FIG. 5 is a block diagram of the eNB 200 (base station). As illustrated in FIG. 5, the eNB 200 includes an LTE communication unit (WWAN communication unit) 210, a control unit 230, and a network communication unit 240. However, in the case of the Collated scenario, the eNB 200 may include the WLAN communication unit 220.

The LTE communication unit 210 performs LTE communication under the control of the control unit 230. The LTE communication unit 210 may execute part of the LTE protocol. The LTE communication unit 210 includes an antenna, a transmitter, and a receiver. The transmitter converts a baseband signal (transmission signal) output from the control unit 230 into an LTE radio signal. The transmitter transmits an LTE radio signal from the antenna. The receiver converts the LTE radio signal received by the antenna into a baseband signal (received signal). The receiver outputs the baseband signal to the control unit 230.

The WLAN communication unit 220 performs WLAN communication under the control of the control unit 230. The WLAN communication unit 220 may execute part of the WLAN protocol. The WLAN communication unit 220 includes an antenna, a transmitter, and a receiver. The transmitter converts a baseband signal (transmission signal) output from the control unit 230 into a WLAN radio signal. The transmitter transmits a WLAN radio signal from the antenna. The receiver converts the WLAN radio signal received by the antenna into a baseband signal (received signal). The receiver outputs the baseband signal to the control unit 230.

The control unit 230 performs various controls in the eNB 200. The control unit 230 may execute part of the LTE protocol or may execute part of the WLAN protocol. The control unit 230 includes a processor and a memory. The memory stores a program executed by the processor and information used for processing by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of the baseband signal. The CPU may include a CPU that executes a program stored in the memory and performs various processes. The processor executes various processes described later.

The network communication unit 240 is connected to the adjacent eNB 200 via the X2 interface. The network communication unit 240 is connected to the EPC 500 (MME / S-GW) via the S1 interface. The network communication unit 240 is connected to the WT 400 via the Xw interface. The network communication unit 240 is used for communication performed via the X2 interface, communication performed via the S1 interface, communication performed via the Xw interface, and the like.

(5) Configuration of WLAN Terminal Node FIG. 6 is a block diagram of WT 400 (WLAN terminal node). As shown in FIG. 6, the WT 400 includes a control unit 410 and a network communication unit 420.

The control unit 410 performs various controls in the WT 400. The control unit 410 includes a processor and a memory. The memory stores a program executed by the processor and information used for processing by the processor. The processor may include a CPU that executes a program stored in the memory and performs various processes. The processor executes various processes described later.

The network communication unit 420 is connected to the eNB 200 via the Xw interface. The network communication unit 420 is connected to the WLAN AP 300 via an interface in the WLAN 20. The network communication unit 420 is used for communication performed via the Xw interface.

[Outline of LWA]
An outline of LWA will be described.

(1) Radio Protocol Configuration FIG. 7 is a diagram showing a radio protocol configuration of LWA. Here, downlink LWA is described, but LWA can also be applied to uplink. In the LWA, the UE 100 in the RRC connected mode is configured by the eNB 200 to use the LTE radio resource and the WLAN radio resource. In LWA, a bearer in which the corresponding radio protocol exists in both eNB 200 and WLAN 20 so as to use both eNB resource and WLAN resource may be referred to as “LWA bearer”.

As shown in FIG. 7, data of one bearer (MCG Bearer) of the UE 100 is transmitted from the eNB 200 to the UE 100. At least a part of the data of other bearers (Split Bearer, Switched Bearer) of the UE 100 is transmitted from the eNB 200 to the UE 100 via the WT 400 (WLAN 20). The other bearer corresponds to an LWA bearer. Only one of the Split Bearer and the Switched Bearer may be used.

The eNB 200 includes a PDCP entity and an RLC entity corresponding to the MCG Bearer. The PDCP entity processes data (PDCP SDU) transferred from the S-GW 500U via the S1 interface. The PDCP entity delivers the processed data (PDCP PDU) to the RLC entity. The RLC entity obtains data from the PDCP entity as an RLC SDU. The RLC entity delivers the processed data (RLC PDU) to the LTE MAC entity. The LTE MAC entity acquires data from the RLC entity as a MAC SDU. The LTE MAC entity transmits the processed data (MAC PDU) to the UE 100 via a physical layer entity (not shown).

The eNB 200 may include a PDCP entity corresponding to the Split Bearer, an RLC entity, and “DRB ID Addon”. The PDCP entity processes data (PDCP SDU) transferred from the S-GW 500U via the S1 interface. The PDCP entity delivers at least part of the processed data (PDCP PDU) as an LWA PDU to “DRB ID Addition”. “DRB ID Additon” adds a DRB (Data Radio Bearer) identifier to the LWA PDU and transfers it to the WT 400 via the Xw interface. The remaining PDCP PDUs are delivered to the RLC entity and transmitted to the UE 100 through the same processing as the MCG Bearer.

The eNB 200 may include a PDCP entity corresponding to the Switched Bearer and “DRB ID Addon”. The PDCP entity processes data (PDCP SDU) transferred from the S-GW 500U via the S1 interface. The PDCP entity delivers the processed data (PDCP PDU) as an LWA PDU to “DRB ID Addon”. “DRB ID Additon” adds the DRB identifier to the LWA PDU and transfers it to the WT 400 via the Xw interface.

(2) WT Addition Procedure FIG. 8 is a diagram showing a WT addition procedure (WT Addition procedure). The WT addition procedure is initiated by the eNB 200 to establish a UE context in the WT 400 to provide WLAN resources to the UE 100.

In step S11, the eNB 200 requests the UE 100 to report the LWA radio access capability of the UE 100 (UE Capability Enquiry).

In Step S12, the UE 100 reports to the eNB 200 the LWA capability (UE Capability Information) including the WLAN band to be supported.

In step S13, the eNB 200 sets a WLAN measurement report in the UE 100. Such setting is performed by a “RRC Connection Reconfiguration” message that is dedicated RRC signaling addressed to the UE 100.

In step S 14, the UE 100 applies the measurement setting, and transmits an “RRC Connection Reconfiguration Complete” message to the eNB 200.

In step S15, the UE 100 acquires WLAN information based on the measurement setting.

In step S16, the UE 100 transmits a measurement report (Measurement Report) including a measurement result for the WLAN 20 (WLAN AP 300) to the eNB 200. Hereinafter, such a measurement report is referred to as a “WLAN measurement report”. The WLAN measurement report includes the WLAN identifier and WLAN metric value where the measurement was made. The WLAN metric value includes, for example, WLAN channel use (BSS load), WLAN backhaul data rate, WLAN signal strength (Beacon RSSI), and the like.

In step S17, the eNB 200 determines to request the WT 400 to allocate the WLAN resource to the bearer of the UE 100 based on the WLAN measurement report. The eNB 200 transmits a “WT Addition Request” message to the WT 400 via the Xw interface. The addition request (WT Addition Request) includes context information (UE Context) of the UE 100.

In step S18, if the WT 400 can approve the WLAN resource request, the WT 400 transmits a “WT Addition Request Acknowledge” message to the eNB 200 via the Xw interface.

In step S19, the eNB 200 transmits a “RRC Connection Reconfiguration” message including a new radio resource setting to the UE 100.

In step S20, the UE 100 applies the new radio resource setting, and transmits an “RRC Connection Reconfiguration Complete” message to the eNB 200.

In step S 21, the UE 100 performs connection processing (association) with the WLAN 20. Hereinafter, the connection process (association) between the UE 100 and the WLAN 20 is referred to as “WLAN association”.

In step S22, the WLAN 20 transmits a “WT Association Configuration” message indicating that the WLAN association between the UE 100 and the eNB 200 is successful to the eNB 200 via the Xw interface.

[First Embodiment]
A first embodiment will be described.

In the WT addition procedure described above, the WLAN association between the UE 100 and the WLAN 20 is not always successful. However, at present, the behavior when the WLAN association fails is not examined, and it is unclear how to determine the failure of the WLAN association. In particular, when the WLAN association fails, the eNB 200 may continue to wait for the “WT Association Configuration” message even though the WLAN 20 does not transmit the “WT Association Configuration” message.

(1) Base Station According to First Embodiment As shown in FIG. 8, the control unit 230 (see FIG. 5) of the eNB 200 (base station) according to the first embodiment has an Xw interface with the eNB 200. On the other hand, a process of transmitting a request message for requesting resource allocation to the UE 100 connected to the eNB 200 (step S17: WT Addition Request) and a process of receiving an acknowledgment message for the request message from the WT 400 (step S18: WT Addition) (Request Acknowledge), a process for transmitting a setting message for instructing WLAN association to the UE 100 (step S19: RRC Connection Reconfiguration), and a setting message. Process of receiving the setting completion message for message from UE 100: (step S20 RRC Connection Reconfiguration Complete), is carried out.

In response to reception of an acknowledgment message (step S18: WT Addition Request Acknowledge) or a setting completion message (step S20: RRC Connection Reconfiguration Complete), the control unit 230 causes a WLAN association failure between the UE 100 and the WLAN. Start a timer to determine. Note that the timer may be set in the eNB 200 using an OAM (Operation Administration Maintenance) function.

Thereby, the eNB 200 can wait for a certain period of time until the WLAN association is successful. When a certain time has elapsed (that is, when the timer has expired), the eNB 200 can determine that the WLAN association has failed.

In the first embodiment, when the eNB 200 receives from the WT 400 a confirmation message (WT Association Configuration) indicating that the WLAN association is successful while the timer is running, the control unit 230 stops the timer. When the timer expires without the eNB 200 receiving a confirmation message (WT Association Configuration) from the WT 400 during the operation of the timer, the control unit 230 determines that the WLAN association has failed. Thereby, eNB200 can determine appropriately whether WLAN association failed based on the confirmation message (WT Association Configuration).

(2) Operation pattern 1 of the base station according to the first embodiment
FIG. 9 is a flowchart showing an operation pattern 1 of the eNB 200 (base station) according to the first embodiment.

As shown in FIG. 9, in step S 101, the control unit 230 transmits to the WT 400 a “WT Addition Request” message that requests allocation of resources to the UE 100 connected to the eNB 200.

In step S 102, the control unit 230 receives a “WT Addition Request Acknowledge” message from the WT 400 that is an affirmative response message to the “WT Addition Request” message. When the control unit 230 receives a negative response message from the WLAN 20 in response to the “WT Addition Request” message, the control unit 230 may cancel this flow. The control unit 230 starts a timer for determining the failure of the WLAN association between the UE 100 and the WLAN.

In step S103, the control unit 230 transmits an “RRC Connection Reconfiguration” message to the UE 100 to instruct WLAN association.

In step S 104, the control unit 230 receives a “RRC Connection Reconfiguration Complete” message from the UE 100. When the control unit 230 receives a negative response message for the “RRC Connection Reconfiguration” message from the UE 100, the control unit 230 may cancel this flow.

When the eNB 200 receives a “WT Association Configuration” message indicating that the WLAN association is successful while the timer is running (step S105: Yes), the control unit 230 stops the timer in step S106. Let

If the eNB 200 does not receive the “WT Association Configuration” message from the WT 400 during the operation of the timer (step S105: No) and the timer has expired (step S107: Yes), in step S108, the control unit 230 causes the WLAN association. Is determined to have failed.

(3) Operation pattern 2 according to the first embodiment
FIG. 10 is a flowchart showing an operation pattern 2 of the eNB 200 (base station) according to the first embodiment. Here, differences from the operation pattern 1 will be mainly described.

As shown in FIG. 10, in step S 131, the control unit 230 transmits a “WT Addition Request” message to the WT 400.

In step S 132, the control unit 230 receives a “WT Addition Request Acknowledge” message from the WT 400.

In step S133, the control unit 230 transmits a “RRC Connection Reconfiguration” message for instructing WLAN association to the UE 100.

In step S 134, the control unit 230 receives the “RRC Connection Reconfiguration Complete” message from the UE 100. The control unit 230 starts a timer for determining the failure of the WLAN association between the UE 100 and the WLAN.

Subsequent operations (steps S135 to S138) are the same as those of the operation pattern 1.

(4) Operation at the time of WLAN association failure determination When the timer expires (that is, when it is determined that the WLAN association has failed), the control unit 230 performs any one of the first to third processes.

The first process is a process of requesting the WT 400 to release resources for the UE 100. That is, the first process is a process for preventing LWA from being performed. Specifically, control unit 230 transmits a “WT Release Request” message to WT 400 (first WT) that has transmitted a “WT Addition Request Acknowledge” message to eNB 200.

The second process is a process of requesting the resource allocation for the UE 100 to a different WT (second WT) and requesting the resource release for the UE 100 to the original WT (first WT). That is, the second process is a process of trying LWA by a WT different from the original WT (first WT). Specifically, control unit 230 transmits a “WT Addition Request” message to a different WT (second WT). Control unit 230 then transmits a “WT Release Request” message to the original WT (first WT).

The third process is a process of changing the WLAN mobility set to be set in the UE 100 and requesting the WT 400 to change the mobility set. That is, the third process is a process of changing the WLAN mobility set to be set in the UE 100 without changing the original WT (first WT). Specifically, the control unit 230 transmits a “WT Modification Request” message to the original WT (first WT) and transmits an “RRC Connection Reconfiguration” message to the UE 100. Here, when the WLAN 20 knows the WLAN mobility set newly set in the UE 100, when the UE 100 performs AP switching in the WLAN mobility set, data transfer from the source AP to the target AP is performed smoothly. Can do.

The control unit 230 performs a process of receiving a WLAN measurement report (see step S16 in FIG. 8) from the UE 100, and performs one of the first to third processes based on information included in the WLAN measurement report. You may decide.

Specifically, when the WLAN measurement report from the UE 100 does not include AP information other than the AP included in the WLAN mobility set currently set in the UE 100, the control unit 230 selects the first process. .

When the WLAN measurement report from the UE 100 includes information on an AP other than the AP included in the WLAN mobility set currently set in the UE 100, and the AP belongs to a different WT (second WT), control is performed. The unit 230 selects the second process. For example, the control unit 230 can grasp the WT to which the AP belongs by making an inquiry to the OAM or the like based on the AP information (WLAN identifier).

When the WLAN measurement report from the UE 100 includes AP information other than the AP included in the WLAN mobility set currently set in the UE 100, and the AP belongs to the same WT (first WT), The control unit 230 selects the third process.

[Second Embodiment]
A second embodiment will be described.

In the first embodiment, the eNB 200 determines whether or not the WLAN association has failed based on the “WT Association Configuration” message from the WT 400. In contrast, in the second embodiment, the eNB 200 determines whether the WLAN association has failed based on a WLAN association success notification (hereinafter referred to as “Successful Indication”) from the UE 100.

(1) Wireless terminal according to the second embodiment The control unit 130 (see FIG. 4) of the UE 100 (wireless terminal) according to the second embodiment sends a setting message for instructing WLAN association, as shown in FIG. A process (step S19: RRC Connection Reconfiguration) received from the eNB 200 and a process of transmitting a setting completion message for the setting message to the eNB 200 (step S20: RRC Connection Reconfiguration Complete) are performed.

The control unit 130 starts a timer for determining the failure of the WLAN association between the UE 100 and the WLAN 20 in response to the transmission of the setting completion message. The timer is set by the eNB 200. For example, the eNB 200 may set a timer in the UE 100 with a “RRC Connection Reconfiguration” message. For example, the eNB 200 may set a timer in the UE 100 by broadcast using SIB (System Information Block).

If the WLAN association is successful during the timer operation, the control unit 130 stops the timer. When the WLAN association is successful during the operation of the timer, the control unit 130 transmits “Successful Indication” indicating the success of the WLAN association to the eNB 200.

When the WLAN association is not successful during the operation of the timer and the timer expires, the control unit 130 determines that the WLAN association has failed. When the timer expires, the control unit 130 stops transmitting “Successful Indication” to the eNB 200.

FIG. 11 is a flowchart showing the operation of the UE 100 according to the second embodiment.

As shown in FIG. 11, in step S 201, the control unit 130 receives an “RRC Connection Reconfiguration” message from the eNB 200 for instructing WLAN association.

In Step S202, the control unit 130 transmits an “RRC Connection Reconfiguration Complete” message to the eNB 200. The control unit 130 starts a timer for determining the failure of the WLAN association. The control unit 130 starts a trial of WLAN association. The control unit 130 may repeatedly try WLAN association as long as the timer is operating.

When the WLAN association is successful during the operation of the timer (step S203: Yes), in step S204, the control unit 130 stops the timer. The control unit 130 transmits “Successful Indication” indicating the success of the WLAN association to the eNB 200.

If the WLAN association is not successful during the operation of the timer (step S203: No) and the timer has expired (step S205: Yes), in step S206, the control unit 130 determines that the WLAN association has failed. In this case, the control unit 130 does not transmit “Successful Indication” to the eNB 200. The control unit 130 stops the WLAN association trial.

(2) Base Station According to Second Embodiment The control unit 230 (see FIG. 5) of the eNB 200 (base station) according to the second embodiment manages a timer having the same time as the timer set in the UE 100. The control unit 230 starts a timer in response to receiving the “RRC Connection Reconfiguration Complete” message from the UE 100.

When the “Successful Indication” indicating that the WLAN association is successful is received from the UE 100 during the operation of the timer, the control unit 230 stops the timer. When the timer expires without receiving “Successful Indication” from the UE 100 during the operation of the timer, the control unit 230 determines that the WLAN association has failed. The operation performed when it is determined that the WLAN association has failed (operation when determining WLAN association failure) is the same as in the first embodiment.

FIG. 12 is a flowchart showing the operation of the eNB 200 (base station) according to the second embodiment. Differences from the first embodiment will be mainly described.

As shown in FIG. 12, in step S 231, control unit 230 transmits a “WT Addition Request” message to WT 400.

In step S232, control unit 230 receives a “WT Addition Request Acknowledge” message from WT 400.

In step S233, the control unit 230 transmits a “RRC Connection Reconfiguration” message to the UE 100 to instruct the WLAN association.

In step S234, the control unit 230 receives the “RRC Connection Reconfiguration Complete” message from the UE 100. The control unit 230 starts a timer for determining the failure of the WLAN association between the UE 100 and the WLAN.

When the eNB 200 receives from the UE 100 “Successful Indication” indicating that the WLAN association is successful during the operation of the timer (step S235: Yes), the control unit 230 stops the timer in step S236.

When the timer has expired (step S235: Yes) when the eNB 200 does not receive “Successful Indication” from the UE 100 during the timer operation (step S235: No), the control unit 230 causes the WLAN association to fail in step S238. It is determined that

[Third Embodiment]
A third embodiment will be described.

In the first embodiment and the second embodiment, it is determined whether or not the WLAN association has failed using a timer managed by the eNB 200. In the third embodiment, a timer managed by the WT 400 is used to determine whether or not the WLAN association has failed.

The control unit 410 (see FIG. 6) of the WT 400 according to the third embodiment receives, from the eNB 200, a request message for requesting resource allocation to the UE 100 connected to the eNB 200 (step S17: WT), as illustrated in FIG. Addition Request) and processing for transmitting an acknowledgment message to the request message to the eNB 200 (Step S18: WT Addition Request Acknowledge). The control unit 410 starts a timer for determining the failure of WLAN association between the UE 100 and the WLAN in response to the transmission of the acknowledgment message. The timer may be set in the WT 400 by the OAM function. The timer may be set in the WT 400 by the eNB 200.

If the WLAN association is successful while the timer is operating, the control unit 410 stops the timer. In this case, control section 410 transmits a “WT Association Configuration” message to eNB 200.

When the timer expires without success of the WLAN association during the operation of the timer, the control unit 410 determines that the WLAN association has failed. When the timer expires, control unit 410 transmits to eNB 200 a failure message (hereinafter referred to as “WT Association Failure”) indicating a failure of WLAN association.

Thereby, the eNB 200 can recognize that the WLAN association has failed based on the “WT Association Failure” message. Specifically, the eNB 200 determines that the WLAN association has failed in response to receiving the “WT Association Failure” message from the WT 400. The operation when it is determined that the WLAN association has failed (operation when determining WLAN association failure) is the same as in the first embodiment.

The control unit 410 may include information indicating the cause of the failure of the WLAN association in the “WT Association Failure” message. As such cause, for example, it may be indicated that the failure of the WLAN association is caused by a problem on the WLAN 20 (WT 400) side.

FIG. 13 is a flowchart showing the operation of the WT 400 according to the third embodiment.

As illustrated in FIG. 13, in step S 301, the control unit 410 receives a “WT Addition Request” message from the eNB 200.

In step S302, control unit 410 transmits a “WT Addition Request Acknowledge” message to eNB 200. The control unit 410 starts a timer for determining the failure of the WLAN association.

If the WLAN association is successful during the operation of the timer (step S303: Yes), in step S304, the control unit 410 stops the timer. Control unit 410 transmits a “WT Association Configuration” message to eNB 200.

If the WLAN association is not successful during the operation of the timer (step S303: No) and the timer has expired (step S305: Yes), in step S306, the control unit 410 determines that the WLAN association has failed. The control unit 410 transmits a “WT Association Failure” message indicating the failure of the WLAN association to the eNB 200.

[Fourth Embodiment]
A fourth embodiment will be described.

In the first embodiment and the second embodiment, it is determined whether or not the WLAN association has failed using a timer managed by the eNB 200. In the third embodiment, a timer managed by the WT 400 is used to determine whether or not the WLAN association has failed. In the fourth embodiment, a timer managed by the UE 100 is used to determine whether or not the WLAN association has failed.

The control unit 130 (see FIG. 4) of the UE 100 (wireless terminal) according to the fourth embodiment, between the UE 100 and the WLAN 20, in response to the transmission of the “RRC Connection Reconfiguration Complete” message, similarly to the second embodiment. Start a timer to determine WLAN association failure. The timer is set by the eNB 200. For example, the eNB 200 may set a timer in the UE 100 with a “RRC Connection Reconfiguration” message. For example, the eNB 200 may set a timer in the UE 100 by broadcast using SIB (System Information Block).

If the WLAN association is successful during the timer operation, the control unit 130 stops the timer. When the WLAN association is successful during the operation of the timer, the control unit 130 may transmit “Successful Indication” indicating the success of the WLAN association to the eNB 200.

When the WLAN association is not successful during the operation of the timer and the timer expires, the control unit 130 determines that the WLAN association has failed. When the timer expires, the control unit 130 transmits “Association Failure”, which is a failure notification indicating that the WLAN association has failed, to the eNB 200.

Thereby, the eNB 200 can recognize that the WLAN association has failed based on the “Association Failure” from the UE 100. Specifically, the eNB 200 determines that the WLAN association has failed in response to receiving “Association Failure” from the UE 100. The operation performed when it is determined that the WLAN association has failed (operation when determining WLAN association failure) is the same as in the first embodiment. The “Association Failure” may include information indicating the cause of the failure of the WLAN association.

FIG. 14 is a flowchart showing the operation of the UE 100 according to the fourth embodiment.

As shown in FIG. 14, in step S 401, the control unit 130 receives an “RRC Connection Reconfiguration” message from the eNB 200 for instructing WLAN association.

In step S 402, the control unit 130 transmits an “RRC Connection Reconfiguration Complete” message to the eNB 200. The control unit 130 starts a timer for determining the failure of the WLAN association. The control unit 130 starts a trial of WLAN association. The control unit 130 may repeatedly try WLAN association as long as the timer is operating.

If the WLAN association is successful during the operation of the timer (step S403: Yes), in step S404, the control unit 130 stops the timer. The control unit 130 may transmit “Successful Indication” indicating the success of the WLAN association to the eNB 200.

If the WLAN association is not successful during the operation of the timer (step S403: No) and the timer has expired (step S405: Yes), in step S406, the control unit 130 determines that the WLAN association has failed. The control unit 130 transmits “Association Failure” to the eNB 200. In addition, the control unit 130 stops the WLAN association attempt.

[Other Embodiments]
In 2nd Embodiment and 4th Embodiment mentioned above, the example which sets a timer with respect to UE100 from eNB200 was demonstrated. However, a counter may be used instead of the timer. Specifically, eNB200 sets the upper limit of the number of times of WLAN association trials to UE100. UE100 counts the frequency | count of trial of WLAN association, and when a count value reaches an upper limit, it determines with WLAN association having failed. Other operations are the same as those in the second embodiment and the fourth embodiment.

In each embodiment described above, the eNB 200, the WT 400, and the UE 100 stop their timers, and then reset (clear) the timers or set them to initial values. The eNB 200, the WT 400, and the UE 100 reset (clear) the timer or set the initial value after the timer has expired.

In each embodiment described above, the LTE system is exemplified as the WWAN system. However, the present invention is not limited to LTE systems. The present invention may be applied to a WWAN system other than the LTE system.

The entire contents of Japanese Patent Application No. 2015-218938 (filed on November 6, 2015) are incorporated herein by reference.

The present invention is useful in the field of wireless communication.

Claims

A wireless terminal connected to a WWAN (Wireless Wide Area Network) base station,
Receiving a setting message for instructing connection processing between the wireless terminal and a WLAN (Wireless Local Area Network) from the base station;
A process of receiving timer information for setting a timer for determining a failure of a connection process between the wireless terminal and the WLAN included in the setting message;
Processing to start a timer based on the timer information;
A process for determining that the connection process has failed when the timer expires;
A process of transmitting a failure message indicating the failure of the connection process to the base station;
A wireless terminal comprising a control unit for performing
The wireless terminal according to claim 1, wherein when the connection process is successful during the operation of the timer, the control unit stops the timer.
The wireless terminal according to claim 1, wherein when the connection process is successful while the timer is operating, the control unit transmits a success notification indicating the success of the connection process to the base station.
A WWAN (Wireless Wide Area Network) base station,
A process of transmitting a request message for requesting resource allocation to a wireless terminal connected to the base station to a WLAN (Wireless Local Area Network) terminal node having an interface with the base station;
Receiving an acknowledgment message for the request message from the WLAN termination node;
A control unit that performs a process of transmitting a setting message for instructing a connection process between the wireless terminal and the WLAN to the wireless terminal;
The control unit includes a timer information for setting a timer for determining a failure of a connection process between the wireless terminal and the WLAN in the setting message.
A WWAN (Wireless Wide Area Network) base station,
A process of transmitting a request message for requesting resource allocation to a wireless terminal connected to the base station to a WLAN (Wireless Local Area Network) terminal node having an interface with the base station;
Receiving an acknowledgment message for the request message from the WLAN termination node;
Processing for transmitting a setting message for instructing connection processing between the wireless terminal and the WLAN to the wireless terminal;
A process of receiving a setting completion message for the setting message from the wireless terminal;
A base comprising a control unit that performs a process of starting a timer for determining a failure of a connection process between the wireless terminal and the WLAN in response to reception of the acknowledgment message or the setting completion message Bureau.
When the base station receives a confirmation message indicating that the connection process is successful during the operation of the timer from the WLAN termination node, the control unit stops the timer,
The control unit determines that the connection process has failed when the timer expires without the base station receiving the confirmation message from the WLAN termination node during operation of the timer. Base station.
During the operation of the timer, when the base station receives a success notification indicating that the connection process has been successful from the wireless terminal, the control unit stops the timer,
The control unit determines that the connection process has failed when the timer expires without the base station receiving the success notification from the wireless terminal during the operation of the timer. base station.
When the timer expires, the control unit performs any one of the first to third processes,
The first process is a process of requesting the WLAN end node to release resources for the wireless terminal,
The second process is a process of requesting resource allocation for the wireless terminal to a WLAN terminal node different from the WLAN terminal node and requesting the WLAN terminal node to release resources for the wireless terminal. Yes,
The base station according to claim 6, wherein the third process is a process of changing a WLAN mobility set to be set in the wireless terminal and requesting the WLAN end node to change the mobility set.
The controller is
A process of receiving a WLAN measurement report from the wireless terminal;
The base station according to claim 8, wherein one of the first to third processes is determined based on information included in the WLAN measurement report.
A WLAN (Wireless Local Area Network) terminal node having an interface with a base station of a WWAN (Wireless Wide Area Network),
A process of receiving a request message from the base station for requesting allocation of resources to a wireless terminal connected to the base station;
Processing to transmit an acknowledgment message to the request message to the base station;
A WLAN termination node comprising a control unit that performs a process of starting a timer for determining a failure of a connection process between the wireless terminal and a WLAN in response to transmission of the acknowledgment message.
When the connection process is successful during the operation of the timer, the control unit stops the timer,
The WLAN termination node according to claim 10, wherein, when the connection process is not successful during the operation of the timer and the timer expires, the control unit determines that the connection process has failed.
The WLAN termination node according to claim 11, wherein when the timer expires, the control unit performs a process of transmitting a failure message indicating failure of the connection process to the base station.
The WLAN termination node according to claim 12, wherein the control unit includes information indicating a cause of the failure of the connection process in the failure message.
A WWAN (Wireless Wide Area Network) base station,
A process of transmitting a request message for requesting resource allocation to a wireless terminal connected to the base station to a WLAN (Wireless Local Area Network) terminal node having an interface with the base station;
Receiving an acknowledgment message for the request message from the WLAN termination node;
Processing for transmitting a setting message for instructing connection processing between the wireless terminal and the WLAN to the wireless terminal;
It is determined that the connection process has failed in response to receiving a failure message indicating failure in the connection process from the WLAN terminal node or receiving a failure notification indicating failure in the connection process from the wireless terminal. And a base station comprising a control unit for performing the processing.
The control unit that determines that the connection process has failed performs any one of the first to third processes,
The first process is a process of requesting the WLAN end node to release resources for the wireless terminal,
The second process is a process of requesting resource allocation for the wireless terminal to a WLAN terminal node different from the WLAN terminal node and requesting the WLAN terminal node to release resources for the wireless terminal. Yes,
The base station according to claim 14, wherein the third process is a process of changing a WLAN mobility set to be set in the wireless terminal and requesting the WLAN end node to change the mobility set.
The controller is
A process of receiving a WLAN measurement report from the wireless terminal;
The base station according to claim 15, wherein one of the first to third processes is determined based on information included in the WLAN measurement report.